BioCycle November 2010, Vol. 51, No. 11, p. 11
ANAEROBIC DIGESTER ON UNIVERSITY CAMPUS
The University of Guelph’s Ridgetown Campus, part of the Ontario Agriculture College (OAC), received an investment of more than $2.6 million for construction of an anaerobic digester through the Federal Development Agency for Southern Ontario. OAC, with its Center for Agricultural Renewable Energy and Sustainability, views the digester as “a breeding ground for new methods and technologies that can be adopted throughout Ontario to add additional revenue streams to family farms,” says Art Schaafsma, Ridgetown Campus Director. The plant includes a digester, feeder system, pasteurization unit and biogas engine. It will process dairy, swine and beef manure, corn silage and other off-farm wastes. Construction began in September, with the facility expected to be on line and generating biogas by February 2011. The plant was designed and being built by PlanET Biogas Solutions acting as the design-build contractor.
Albany, New York
CAPTURING, USING HEAT FROM COMPOST
The installation of a composting and heat recovery system at a calf-raising operation in Easton, New York (near Albany), marks the second such project for Agrilab Technologies, LLP, of Vermont. The system at Sunset View Farm, which raises dairy calves for 10 large regional dairy farms, is expected to capture in excess of 1,000 btu of energy from each ton of composting feedstock per hour. It is expected to process approximately 500 tons of material weekly, thus generating an average of 190,000 btu/hour, or 4,560,000 btu/day. The composting and heat recovery system should eliminate the farm’s use of propane while dramatically reducing diesel, electric and grid-based energy dependence, says Josh Nelson, Agrilab’s director of operations. The heat will supply the facility’s 11,000 gallon/day hot water needs and warm the buildings on the complex. Finished, stabilized compost will be used as livestock bedding and ultimately be field-applied, reducing chemical fertilizer usage and improving soil health.
The entire system at Sunset View Farm is powered by a one-quarter-HP, in-line electric fan and standard zone valves utilized in common plumbing applications. “This technology is applicable to any farm or facility managing and composting organic waste feedstocks – especially, livestock, greenhouse, aquaculture, slaughterhouses, food processors or regional recycling centers looking to maximize the benefits of food waste diversion through aerobic composting,” says Nelson. “We compost in a building on aerated floors, and continuously pull air down through the pile.” The system draws air through the hot compost piles, which heats water up to 140°F while providing aeration.
COMPOSTING HEATS UP AT DISNEY WORLD
Reedy Creek Improvement District encompasses 25,000 acres in the heart of Central Florida and is home to Walt Disney World Resort. Jerry Vollenweider, Reedy Creek supervisor of waste-water and compost, has been involved with the Magic Kingdom and all of its other resort operations since the mega tourist destination began composting more than 20 years ago.
Reedy Creek began composting in the late 1980s, using a Taulman in-vessel system with outdoor aerated static pile system (ASP. “The in-vessel system was rather maintenance intense and so we decided to go with something little simpler,” says Vollenweider, adding that the ASP system eventually included 28 individual compost piles. “The sludge load-out was right next to our pressing building. We started incorporating food and had some odor issues.” Eventually, Reedy Creek switched to a Wright Environmental in-vessel system for the food waste stream, which utilizes three horizontal tunnels. “With oils, grease and fat going in, it’s tough to get the initial heat going and retention time to fully compost those feedstocks, so after it comes out the other end of the tunnel we truck it to an outdoor facility to finish it off,” explains Vollenweider. The processed material is blended and composted with biosolids coming in from all resort properties, animal manures from Fort Wilderness and Animal Kingdom and landscape debris from within the park as well as from outside. “One thing we buy the most of is ground pallets,” he adds, explaining that the rather temperamental tunnel system requires amendments that are an-inch-and-a-half minus with less than 40 percent moisture to operate properly. Reedy Creek recently acquired a Vermeer Wildcat 626 Cougar trommel screen. Finished compost is screened at one-quarter-inch. “Blending the food feedstock with sludge helps bring the pH up,” says Vollenweider. Most of the compost goes offsite to citrus groves, pasture, sod farms and to the Florida Department of Transportation for maintenance projects.
Lafayette College, a private liberal arts school serving around 2,500 undergraduate students, is diverting about 25 percent of its food waste from landfills using two Earth Tubs, two food pulpers and a successful $41,000 state grant application written by a senior at the college. The Lafayette College Compost Team is a subcommittee of both Lafayette Environmental Awareness and Protection (LEAP) and the Society of Environmental Engineers and Scientists (SEES). Every weeknight, dedicated teams of students haul about 250 pounds of collected and pulped food waste from the dining hall to two commercial-size compost tubs at the edge of campus, where the pulp is weighed and mixed with wood chips in correct proportion. The goal is to divert a full 1,000 pounds daily of food scraps. Compost is used for campus landscape projects as well as the school’s 2-acre community garden. “The garden project wouldn’t have started without the composting program,” says student Jennifer Bell, who wrote the grant application. “This project has really opened my eyes about where everything goes and comes from,” says SEES president and junior Emily Clark. “You go to the grocery store and you have no idea.”
BIOSOLIDS COMPOSTING FACILITY EXPANSION
The Spotsylvania County Department of Utilities/Public Works has achieved 100 percent biosolids diversion from the county’s landfill, thanks to expansion of its composting facility. Originally opened in 2001 as a pilot project, the program was progressively expanded to process more than 12,000 tons/year of biosolids and ground mulch by 2008, according to a news article in the Biosolids Technical Bulletin. The new facility, which opened this past spring, incorporates negative aeration with process air treated in a biofilter and automated control of aeration fans based on temperature feedback. Highlights of the operation include the following: Brush collected within the county is ground and transported to a covered storage area. The mixing area is separated from the compost aeration piles by a concrete push wall to avoid cross-contamination of fresh and composting material. Two Kuhn-Knight stationary mixers blend biosolids and wood chips in a 1:1 ratio; the mixers discharge onto a conveyor that carries the material over the push wall and into a bucket loader, which transport the mixed feedstocks to the aeration bay of the compost hall.
Two biofilter structures are connected to the composting hall through a series of pipes and headers. Each has a humidification and irrigation system to ensure the media – made from screened mulch – is maintained at 60 percent moisture. After 21 days in the aerated bays, the compost is screened in a trommel with.375 inch holes; overs are added back into the raw mix. Material passing through the screen is cured under roof for 30 days. Finished compost, named Livingston Blend, is sold in bulk to landscapers, landscaping suppliers and residents.
San Antonio, Texas
WATER UTILITY PARTNERS WITH PRIVATE COMPANY TO SELL BIOGAS
San Antonio Water System (SAWS), Ameresco, Inc. and local officials teamed up in October for the grand opening of a new biogas facility at the Dos Rios Water Recycling Center. Biogas from the plant’s digesters was previously flared. Via a 20-year partnership with SAWS, Ameresco will treat and transfer at least 900,000 cubic feet of gas to a nearby commercial gas pipeline, where it will be sold on the open market. In return, SAWS ratepayers will receive a royalty on the sale of the gas, estimated at $200,000 annually, thereby reducing customers’ utility bills. “SAWS is constantly improving its operations to become more sustainable, and this project is a sound investment for our environment and our community,” says Robert R. Puente, SAWS president and CEO.
With the addition of the biogas facility, SAWS is recycling and reusing almost all of the waste coming into Dos Rios through what it calls its “recycling trifecta.” Biosolids are also reused to make compost, which is used in landscaping, gardening and agriculture to improve soil quality. The final part of the trifecta is recycled water; about 115 million gallons a day of high-quality recycled water are used for the local Riverwalk, golf courses, parks and for commercial and industrial customers as well as feeding into the upper San Antonio River and Salado Creek.
San Diego County, California
LAWSUIT TARGETS TITANIC RETAILER FOR DUMPING TOXIC WASTE
Following a lawsuit filed last year in Alameda County by prosecutors across California alleging that Minnesota-based Target Corp. routinely disposed various toxic materials improperly at more than 240 stores operating in the state, a judge has ordered the company to stop the practice of dumping hazardous waste that ends up in landfills. The civil enforcement suit claimed the dumping took place over a five-year period and included pesticides, paint, aerosols, oven cleaners, pool chemicals, drain openers and other flammable, toxic and corrosive materials. “It’s time for Target to clean up its act,” San Diego County District Attorney Bonnie Dumanis stated in a press release. “The corporation has been fighting this losing battle for too long, and the California environment is worse off because of it.”
Alameda County Superior Court Judge Steven Brick issued a preliminary injunction September 24 prohibiting Target and its employees from illegally disposing of hazardous waste, using unregistered haulers to transport hazardous waste, transporting hazardous waste without the required manifests and illegally managing and disposing of waste such as batteries, telephones and computer and electronic equipment. California law requires companies to properly store, handle and dispose of hazardous wastes and materials to avoid harm to people and the environment. Prosecutors contend that Target routinely ignored those laws to cut costs and failed to develop and implement an effective program to ensure that employees properly identify defective, damaged and leaking products containing hazardous and toxic chemicals as hazardous waste and dispose of them in accordance with environmental laws rather than throw them into company compactors. Instead of being sent to authorized disposal sites, prosecutors allege tons of hazardous wastes and contaminated materials were crushed along with discarded merchandise and garbage in Target’s compactors and sent to area landfills.
Suffolk County, England
THREE CHEERS FOR BEER-BASED BIOFUEL
One of this historic county’s leading brewers has started generating the nation’s first renewable gas from brewery and local food waste at its innovative anaerobic digestion plant near the seaside resort of Southwold. Adnams Bio Energy is owned by Cambridge-based Bio Group, a renewable energy company to which the Adnams brewery has licensed its name. The new company has formed a partnership with British Gas and National Grid, a UK-based electric and gas company. The goal is to produce sufficient renewable energy to run both the brewery and its fleet of trucks, with the surplus output – projected around 60 percent – going to National Grid customers after required conditioning. The projected amount of gas to be generated approaches 4.8 million kilowatts per year. The plant, which cost just under $4.5 million, consists of three anaerobic digesters with the capacity to break down 12,500 tons of organic waste annually. The first business signed up to supply organics to the digestion plant is Waitrose supermarkets, part of the John Lewis Partnership, which will send food waste from seven regional grocery stores and one John Lewis department store. The arrangement supports that company’s goal to shrink its carbon footprint and divert 95 percent of all waste from landfilling by 2013.
“We are delighted that Adnams Bio Energy is located on the site of our eco distribution center,” said Adnams CEO Andy Wood. “For a number of years now, Adnams has been investing in ways to reduce its impact on the environment. The reality of being able to convert our own brewing waste and local food waste to power our brewery and vehicles, as well as the wider community, is very exciting.” Liquid by-products from the digesters will be used to grow barley for Adnams beer.
November 15, 2010 | General
BioCycle November 2010, Vol. 51, No. 11, p. 11